Physically based renderers, such as Iray, tries to approximate the physics of reality. For each point on the screen, it shoots out a ray from the camera to that point, then tries to determine its color/value. However, it is simply not possible to calculate the value of a point with real-world accuracy, because we would need to sample light coming in from an infinite number of directions.

Therefore, our Iray renderer must guess what the value of a point is by sampling light from a set of different but finite angles. The more samples we collect or iterations we run, the more time it takes, but the better our guess will be. As we collect more and more samples, we will ultimately converge on a likely answer.

Noise arises when we guess incorrectly, so the value of a particular point widely differs from what it should be. As you may have noticed though, some scenes take longer to converge than others, and some scenes are more noisy than others. What then determines the amount of noise in an Iray scene?

Why Is There Noise in My Daz Studio Iray Render and How to Remove It

What Determines the Amount of Noise in an Iray Scene?

Based on my own Daz Studio experiences, Iray scene noise seems most pronounced when there are small, extremely bright areas in the scene. For example, when most of the scene light is coming from small and bright light sources, specular indirect lighting, or doorways and windows.

In the Fantasy Girl with Horns scene above, there are many bright but small areas of light in the environment map because the sun is peeking through the trees. These small areas of light create noise on the water, which gets compounded as it bounces off that surface and hits others objects in the scene (indirect lighting).

For a more simple case of noise and small, very bright areas, I placed a point light between a fantasy woman’s hands. A point light has a small surface area. When it is the main source of light in a scene, there will likely be a lot of noise.

In some cases, our collected samples may miss the small light altogether, creating a dark spot. In other cases, we may randomly sample in the direction of the light, creating a higher value than reality. Depending on the strength of the light, this value may be very high, thereby significantly skewing our average guess.

Below, we have a zoomed in image with just the point light turned on (all other lights are off). Notice that there is quite a lot of noise when a small bright light is producing most of the illumination in the scene.

Zoomed in image with just the point light turned on. Rendered in Daz Studio Iray for about 10 minutes.

If we increase the strength of the point light, then the picture noise increases (see below).

Point light strength increased by a factor of 10. Rendered in Daz Studio Iray for about 10 minutes.

If we render the point light in a volumetric space, there is even more noise. This is because we are sampling for the entire volume (including the points in-between the hands), which increases the frequency of errors.

If we render the point light in a volumetric space, there is also more noise. This is because we are sampling for the entire volume as opposed to just the object surfaces.

Another noise problem area is when there are caustics. Water, for example, bends light (refraction) and focuses it, essentially making the lighted areas smaller and brighter. This creates interesting light patterns on the water floor. However, because of this light bending property, the direction of our pixel samples become even more important and more susceptible to light misses or accidental hits.

The general take-away here is that –

Small bright areas with high values create more noise than wide bright areas.

Specular, reflective, or refractive surfaces can further increase scene noise. Specular and reflective surfaces increase the number of small and bright areas, each of which serves as an indirect light source. By understanding the source of noise in our Daz Studio Iray renders, we can better control it in our images.

How Do We Reduce Noise in Our Iray Render?

I use four key methods to reduce noise in my Daz Studio Iray images.

1. Adjust Iray Render Settings.
2. Increase the amount of light in the scene.
3. Render at a higher resolution (larger image), then resize down to average out the noise.
4. Remove some of the noise in post-work by using despeckle or blur operations in Photoshop.

1. Adjust Iray Render Settings to Reduce Noise

One of the easiest ways to reduce noise in our Iray renders is to increase the number of samples we collect. The more samples we collect, the better our guess will be (i.e. the closer our guess converges to the actual value). We can do this by going to the Render Settings tab, and then selecting Progressive Rendering.

My Render Settings > Progressive Rendering settings.

Many of these parameters control when rendering stops, and may override each other.

• Max Samples – Controls the number of samples collected per-pixel. The more samples we collect, the better our guess will be.
• Max Time – Controls the maximum amount of time before rendering stops. Note that the render will stop when either Max Samples or Max Time is reached. If we have a slower graphics card, we may want to increase Max Time.
• Rendering Quality – Based on Tobor’s experience, this controls when the Iray renderer considers a pixel to be converged. I.e. a higher quality value will take longer to reach a given level of convergence. Of course speed of convergence also depends on our hardware and scene.

  In more practical terms, Sickleyield defines this parameter as a multiplier for Max Samples and Max Time. I.e., it is a quick way to increase or reduce the time at which rendering stops. For example, when doing test renders we may reduce Rendering Quality and then push it up again for our final image.

• Rendering Converged Ratio – As I understand it convergence is a measure of how close our pixel value guess is to its real value. As such, we will never reach 100% convergence, because that is when our guess is 100% accurate, which can only happen when we have the ability to collect an infinite number of samples. As we have seen above, this measure is also partly determined by the Rendering Quality parameter.

I usually render each of my lights separately, so I end my renders manually based on the light layer. There are three more Render Settings parameters that pertain to noise.

• Firefly Filter Enable – Go to Render Settings > Filtering and make sure that Firefly Filter Enable is on. This will get the Iray renderer to filter out some of the noise in our image.
• Caustic Sampler – Go to Render Settings > Optimization. Turn on Caustic Sample *if* we have caustics in our scene. Note that this enables some additional tests in the renderer thereby increasing sampling time, so only turn it on as necessary.
• Architectural Sampler – Go to Render Settings > Optimization. Turn on Architectural Sampler if we have an internal scene with a lot of indirect lighting and light only coming from portals such windows or doors.

This post by Dave Smith has more detail on these Render Setting parameters. Increasing the number of samples collected is probably the most accurate way to reduce noise. However, it can also take a long time to converge.

2. Increase the Amount of Light

Earlier, we saw that scenes with more noise have light primarily coming directly or indirectly from small bright areas. For example, internal scenes where light is only coming from windows or doors.

One way to reduce noise is to increase the amount of light in our scene, for example by adding large mesh lights in an indoor scene or removing unnecessary walls and ceilings. Larger light sources will reduce the amount of noise in our picture. In addition, if we are getting light from many different directions, then the probability of totally missing a light source or getting overly skewed light values will be significantly reduced.

However, a problem with this approach is that we may flood our scene with too much light, thereby losing shadows, shape definition, and scene depth. The image below is an older image of mine where I used a lot of ambient light in 3Delight.

This is an older image of mine where I used a lot of ambient light in 3Delight. Because there is too much light I lose shadows and shape definition.

3. Render at a Higher Resolution

Another simple way to reduce Iray noise is to render our images at a higher resolution (larger size). When we shrink our image down in size, some of the noise will get averaged away. This is a better method than just using blurring techniques to average away the noise because it will retain picture sharpness and detail.

For example, the top image below is rendered at 1024 by 1331 pixels, at 300 iterations, and then cropped in height. The bottom image is rendered at 3000 by 3900 pixels, at 300 iterations, and then reduced in size to 1024 by 1331 pixels (similarly cropped in height). There is a lot less noise in the bottom image without a loss of sharpness or detail.

There is a lot less noise in the higher resolution image (bottom) without a loss of sharpness or detail.

4. Remove Scene Noise in Post-work

We can also remove some of the render noise in post-work using blurring or de-speckling operations. In Photoshop, I use Filter > Noise > Despeckle for less noisy renders and Filter > Blur > Gaussian Blur for noisy renders. The left image below is the original noisy render and the right image has been blurred with Gaussian Blur radius 3 pixels.

Remove Scene Noise with Blur or Despeckle operations.

The problem with Despeckle or Gaussian Blur is that we lose a lot of detail and sharpness, especially in our primary fantasy girl figure. One way to fix this is to create another render with just the girl. By removing the water, we remove a key source of noise in our scene. With a simpler scene, we can also render more iterations for a given time. Then, we use this low-noise image to sharpen the figure in our blurred image. To do this, I select the figure-sharpen layer and set the blending mode to Overlay. Then, I do Filter > Other > High Pass with a radius of 5 pixels.

Left – Gaussian Blurred image with much less noise but loss of detail. Right – Same image but with the girl figure sharpened using the technique described above.

Conclusion

I reduce noise in my Daz Studio Iray renders by using all four of the techniques above. However, I make sure to properly balance them out so that I do not weaken scene lighting, lose scene detail, or spend too much time rendering.

There are other methods for controlling noise in a path tracer like Iray. For example, seeding the renderer differently, clamping maximum light values, and more. However, as far as I know, such render settings are not currently available in Daz Studio. In any case, they each come with their own weakness.

With just the techniques described here though, I am able to get results that I am happy with. The completed Fantasy Girl with Horns image is shown below. We have added all our lights, removed noise, and applied our post-work process.

Final Fantasy Girl with Horns image. We combined all lights, removed noise, and warmed up the image in post.

Alternatively, if we set the Environment Map image to None, we get a set of controls for using the Iray Sun. But why even use the Iray Sun when we already have lighting goodness from our Environment Maps?

• The Iray Sun allows us to create interesting patterns of light and shadow.
• We have very good control of the position of the Sun.
• The functionality comes for free with Daz Studio, so we do not need to look for or purchase environment maps that fit our scene.

Finally, it does not need to be an either-or situation. We can combine both the Iray Sun and Environment Maps to get the advantages of both, while minimizing the drawbacks when used alone. In this tutorial, we discuss how to effectively use the Iray Sun to create artistic images, like the one shown below.

Daz Studio Iray Sunlight Tutorial

1. Picking the Right Environment and Props

The main reason why I use the Iray Sun, is to create compelling and realistic patterns of light and shadow in my 3d-art. For this to happen, I must include the appropriate environment or props in my scene, which will block sunlight in exactly the right way and cast the shadow patterns I want.

A group that works well for this are buildings with interesting entrances for light, such as large windows, breaks on the roof, doorways, and more. For example, the image below uses Abandoned Interiors: Warehouse by Stonemason. By using this building with the Iray sunlight, we create light patterns on both the girl as well as in the background. Some other example buildings that work well with sunlight are The Old Barn by Age of Armour, The Ministry by Stonemason, and Rural Chateau by Jack Tomalin.

The Abandoned Interiors: Warehouse building by Stonemason is a great prop for using with the Iray sunlight because it has breaks in the roof, broken windows, and water on the ground to reflect the light.

Instead of using a single building, we may also create an outside scene with multiple buildings or structures. In this case, we use the buildings or structures themselves to cast our shadows. For example, our first Lady on a Clock image is an outside scene, with an open structure (from DM’s Fantasy Musings) placed over the girl to cast the proper shadows on the clock-face. Many of Stonemason’s external environments, such as The Streets Of Asia, The Enchanted Forest, and Urban Future 4, can be used with sunlight to create interesting shadows.

Creating patterns of light and shadow using The Ministry prop by Stonemason and Iray sunlight.

2. Positioning the Iray Sun

Next, comes the fun part of positioning the sun so that it hits our scene in the right way, and casts our shadows in the right position. The easiest way to do this is by using a spotlight.

• Add a spotlight by doing Create > New Spotlight, and call it Sun-Spotlight.
• Position the spotlight according to where we want our Iray sunlight to come from. This need not be an exact position, as we can refine it in the next step.

Set our active camera to Sun-Spotlight (top-right corner of the viewport).
• Set our active camera to Sun-Spotlight, which will show us exactly what our light is pointing at, what shadow shapes it will cast, and approximately where it will cast them. In this mode, we can also adjust our spotlight position by using the usual camera controls (i.e. we can manipulate our spotlight the same way we manipulate a camera).
• We go to Render Settings > Editor > Environment and set the SS Sun Node parameter to our Sun-Spotlight.
• After we do this, the location of our Iray Sun will be based on our Sun-Spotlight. If we change the position and angle of our Sun-Spotlight, the position and angle of our Iray Sun will also change accordingly.

For example, in the Lady on a Clock image, we set our Sun-spotlight view as shown below. We also place our structure directly in the path of our spotlight, so that it will cast interesting shadows on the clock face. Note that even though the structure is very much in the view of our Sun-Spotlight, we keep the face of the girl clearly visible, which means that it will not be occluded by shadows from our Iray Sun.

Sun-Spotlight camera view of our Lady on a Clock image. We also place our structure directly in the path of our spotlight, but we keep the face of the girl clearly visible.

In the Redhead girl with gun image, we set our Sun-spotlight to shine through a hole on the building roof.

In the Redhead girl with gun image, we set our Sun-spotlight to shine through a hole on the building roof.

Note that there are a series of controls for adjusting the Iray sun. I usually get good results without having to do any additional adjustments, but more details about them can be found here.

3. Combining the Iray Sun with an Environment Map

The Iray Sun is great for creating striking patterns of light. However, it can also create harsh lighting and overly strong shadows especially on the human figures in our scene. The images below compares Iray Sun lighting and lighting from the Tropical Ruins Environment Map.

In the Iray Sunlight image, there are great shadow patterns, but the light is too harsh on the skin.

In the Iray Sun image, there are strong shadows. The shadow silhouette of the girl is very sharp because it is close to the clock face. The circle and spoke pattern from our ceiling structure is more blurry because it is farther away. However, the light is too harsh on the girl’s skin, making it appear too glossy and unrealistic. This is in contrast to the Environment Map image which has softer contrast, producing more realistic looking skin.

To get the best results, we render both images as separate light layers and then combine them in Photoshop.

• Open both image files in Photoshop.
• Select all (Ctrl-A), copy the Environment Map image (Ctrl-C), and paste it (Ctrl-V) into the Iray Sun image file.
• Leave the blending mode at Normal and adjust the opacity of the Environment Map layer so that we get some of the sunlight shadows on the girl’s body, but also maintain the realistic look of her skin.

We adjust the opacity of the Environment Map layer so that we get some of the sunlight shadows on the girl’s body, but also maintain the realistic look of her skin.
• However, the Environment Map layer has weakened the shadows on our clock-face. One way to fix this is to only mask in the figure and remove the background of the image. This makes our figure’s skin be more realistic, but still keeps the strong shadows from our sun.

Only mask in our lady figure for the Environment Map layer. This makes our figure’s skin be more realistic, but still keeps the strong shadows from our sun.

For Iray sunlight, I set the material on my volumetric prop to Atmocam MedLight.

Finally, we may also render our Iray sunlight as a volumetric light to give our scene added atmosphere. I do this in the usual way using AtmoCam for Iray by Marshian. For Iray sunlight, I set the material on my volumetric prop to Atmocam MedLight.

The Redhead Girl with Gun image below has a layer of volumetric sunlight, which gives it added atmosphere in the background.

I do not always use the Iray Sun, but it can be a very valuable tool in our Daz Studio toolbox! 🙂

The Redhead Girl with Gun image has an added layer of volumetric Iray sunlight, which gives it added atmosphere in the background.

Here, I describe the light combination process. In particular, I talk about adjusting light intensities, tinting, and more. Again, I start with the simple Princess of the East image. This image uses the NeoIndia Outfit and Hair Bundle as well as the Mandgadfor ruins in the background.

In the Princess of the East image, I have the following light layers:

• An IBL light layer using Barcelona Rooftops from sIBL Archives.
• A Key, Back, and Fill layer, following the three-point light system.
• A volumetric spotlight layer.

How I Combine My Iray Lights in Photoshop

Step 1 – Control IBL layer intensity

1. I open all light layers in Photoshop.
2. I go to the IBL light file.
3. I right click on the IBL layer and select Duplicate Layer. I rename the duplicate layer IBL.

Duplicate my IBL background layer.

Set the layer blend mode to Screen and control the intensity of my IBL through the layer opacity slider.
4. I select the Background layer, then go to Edit > Fill, and choose Black in the pop-up box. This should fill our Background layer with a solid black color.
5. I select the IBL layer, and set the layer blend mode to Screen.
6. Now I can control the intensity of my IBL light by increasing or decreasing the opacity of that layer.
7. If I want to increase the intensity of the light by more than its original, then I simply duplicate the layer.

I can increase the intensity of my IBL light by more than its original by duplicating my IBL light layer.

Step 2 – Add in Key, Back, and Fill lights

1. I copy my Key, Back, and Fill light layers, and paste them into my working file in Step 1.
2. These layers quite often have speckle noise. To remove this, I go to Filter > Noise > Despeckle. I repeat this operation on each layer until most of the noise is removed.
3. I set the blend mode of each of these layers to Screen.
4. I adjust intensity by changing layer opacity or duplicate the layer, if necessary, similar to what we did for the IBL layer in Step 1.

In this case, I want a strong silhouette to the right, so I want a very strong back light. I achieve this by duplicating the Back layer to double its strength. To further emphasize the strong back light, I weaken the Key layer, by setting its opacity to 30%. I leave my Fill at 100% to lighten my entire figure.

Finally, I also create a duplicate IBL layer and set its opacity to 30%. This allows me to lighten everything in the image, including the backdrop.

Final result after adding in my Key, Back, and Fill lights, and adjusting intensities according to the values above.

Step 3 – Toning, Tinting, and Masks

A few other Photoshop operations that come in especially handy for combining my Iray lights include:

1. Changing light tones with the Levels Filter.
2. Tinting lights with Photo Filters.
3. Lighting areas selectively by using masks.

I illustrate these additional operations using my Luthbelli Classic image. Another useful lighting tip that I use here, is to add another Back light on the left-back side of the scene. In this way, I can add light rims on both the left and right sides of my figures.

Useful Photoshop operations for combining my Daz Studio Iray lights.

1. Changing light tones with the Levels Filter

I use the same process described above to combine my Iray light layers and control their intensities. In this image, I set my IBL opacity to 50%. When I add in my Key light, I find that it is adding too much light to my figure. In particular, I want there to be greater contrast between the left and right sides of the girl’s face.

Too much illumination added by my Key light, so there is not enough contrast in my pin-up girl’s face.

To change this,

1. I select my Key layer, and then add a Levels adjustment layer by going to Layer > New Adjustment Layer > Levels. I make sure to check “Use Previous Layer to Create Clipping Mask” in the pop-up window, so that my Levels adjustment only applies to my Key light.
2. I reduce the level of mid-tones in my Key light (0.70), and increase the level of highlights (201). This article has a detailed description of the Levels adjustment filter in Photoshop.
3. I add my second back light to get a rim on the left side of my figures.
4. The final result is that there is greater contrast between the left and right sides of my pin-up girl’s face.

Changing light tones using the Photoshop Levels Filter

2. Tinting lights with Photo Filters

To make things more interesting, I add my main back light to the image, and tint it blue so that I get a blue rim around the right of my figures.

Tint my Back light blue by using the Photo Filter adjustment layer.

1. I do this by going to Layer > New Adjustment Layer > Photo Filter. Again, I check “Use Previous Layer to Create Clipping Mask” in the pop-up window, so that my Photo Filter adjustment only applies to my main Back light.
2. I set my Photo Filter to Cooling Filter (82), which is a blue color. I then adjust intensity until I get the right level of blue for my Back light, which in this case is at 83%.

I add my main back light to the image, and tint it blue so that I get a blue rim around the right of my figures.

3. Lighting areas selectively by using masks

Blue highlights that I want to remove are marked by the red circles.

Unfortunately, I do not like some of the blue highlights in my current image. In particular, I do not like the sharp highlight on the body of the motorcycle and the blue on my girl’s headdress. To remove these unwanted highlights, I can mask them out.

Masking out certain blue highlights and masking in only the eye areas of my fill light.

1. For the headdress highlights, I just want to remove the blue color. Therefore, I mask out the area in my blue Photo Filter adjustment layer. I do this by selecting the mask layer on my Photo Filter and then painting the area black.
2. For the motorcycle body, I want to totally remove the highlight. To do this, I go to my Back light layer and do Layer > Layer Mask > Reveal All. This creates a layer mask for my Back light. I select my layer mask and paint the area I want to remove black.
3. I add in my Fill light, but I only mask in the eyes area to brighten my pin-up girl’s eyes. To do this, I go to my Fill layer and do Layer > Layer Mask > Hide All. Then, I select my mask layer and only paint the eye area of my figure white.

Finally, I create a layer with all of my lights combined by doing Ctrl-Alt-Shift-E. I set the layer blend mode to Screen and name the layer All. This allows me to brighten all of my lights. In this image, I set the opacity of my All layer to 50%.

And just like that, we are done! In the next tutorials of this series I will discuss my post-work techniques including adding glow, softening effects, creating contrast, and more.

Final image with all my Iray lights combined including IBL, Key, Back, Back2, Fill, and All.

I use three main classes of lights in all my Iray scenes-

1. An image based light (IBL). This is a HDR image that I use in Render Settings > Environment > Environment Map.
2. Three mesh lights arranged according to the three-point light system.
3. One or more volumetric lights for softening effects and atmosphere.

Then, I may add point-lights or emissive surfaces based on composition.

How I Light My Daz Studio Iray Scenes

We will use the image above to illustrate the different classes of lights and why we use them, in this tutorial. The outfit and hair used in the image are from the NeoIndia Outfit and Hair Bundle by Arki and Shox-Design. The ruins in the backdrop is Mandgadfor by powerage.

1. Image Based Light (IBL)

I usually use a HDR image for this to provide my scene with –

• Realistic ambient lighting.
• Realistic reflections.
• Realistic background that is consistent with both lighting and reflections.

This beginner Iray tutorial has more on how I use a HDR image in Daz Studio Iray.

How well our IBL illuminates the scene will depend in large part on the HDR image we are using. In particular, what range of values it supports. The higher the range, the better the results.

I think about it this way … sunlight is a very strong light source, and its value should be many many times greater than anything else in the scene. Using a regular JPG image that only supports 255 values per pixel, is not going to work well for scene lighting. This is because the difference in range between our very bright sunlight and everything else will be overly compressed. I.e. a lot of light information in our IBL would be lost due to range limits.

A decent JPG can serve as a good enough background, but it will not be sufficient for providing good realistic scene lighting.

Below is our Princess of the East image, with just the IBL turned on. Here, we are using the Barcelona Rooftops HDRI from sIBL Archives. Here is a list of free HDRi sites. Dimension Theory and Orestes Graphics also has some great HDRi’s for Iray.

Scene lighted with just an IBL (Iray Environment Map).

2. Mesh Lights

If we are already using a good HDR image, why do we need to add mesh lights?

I add mesh lights to highlight my main figure(s) and make them stand-out from the rest of the scene. This is especially important in figure based compositions, because the focus of the image is on the main actor(s) in the scene.

I think about it this way … when we go out walking in the streets, the scene around us is very busy. Although we may imagine ourselves to be the center of attention, no single individual stands out from the rest. This is what we get with a HDR image.

In contrast, during a model photo-shoot, lights are added to bring out the figure so that it grabs the viewer’s attention.

1. To highlight my main figure(s), I add three Daz Studio spotlights (Create > New Spotlight).
2. I place my three lights according to the three-point light system (key, fill, back).
3. Then, I convert each of my spotlights into mesh lights by setting the Light Geometry parameter to Rectangle. This will give me softer shadows. For more details on how to convert a spotlight into a mesh light refer to this article.
4. I want my back light to have the sharpest shadows, so I set its size to be the smallest of the three. I want my fill light to have the softest shadows, so it gets the largest rectangle. The key light is somewhere in-between the two.
5. Finally, I select my three lights and add them to a group (Create > New Group), so that I can move them and rotate them together. In this way, I can easily center my three lights around the main figures within my Daz Studio scene.

To bring out my main figure(s), I add three lights according to the three-point light system.

After adding the three mesh lights to my IBL, my figure stands out a lot more from the background, and there is a much stronger silhouette on my figure. If we compare this image and the previous one, with just the IBL, we can clearly see that the lighting is more compelling here and the figure pops from the background.

If you do not want to create a light rig from scratch, the BOSS Pro Light Set for Portraits & Promos has ready-made key, fill, rim lights, and much more.

After adding my three mesh lights to my IBL, my figure stands out a lot more from the background.

3. Volumetric Light

I also like to add at least one volumetric light to my images to provide additional shadows and atmosphere. In this case, I add a spotlight shining onto my figure’s face. I then render it as a volumetric light by using Marshian’s AtmoCam for Iray.

You can also create your own volumetric light. Here are a few ways.

Add a volumetric spotlight shining on our figure’s face. This adds more shadows and atmosphere.

Finally, I re-tone the image some, add a little bit of glow, add some contrast, and I am done!

You will notice that I do not talk much about light intensities in this tutorial. This is because I usually render each light in a separate layer, and later combine them in Photoshop. I control intensity, tint, and more from within Photoshop.

Depending on how I combine these lights, I can create a day-time scene or a sunset scene. I can create a realistic image or a colorful fantasy setting.

By combining lights differently in Photoshop, I can get a day-time or sunset scene; a realistic or a fantasy scene.

Creating wet skin involves three key steps-
1. Making the composition fit. If our figure is to have wet skin, then we want our composition to support that.
2. Making the skin properly shiny. Wet skin is more shiny and reflective than dry skin because there is water on the skin’s surface.
3. Adding water drops on top of the skin. In addition to being more shiny, there will also be some drops of water clinging to the skin, and trailing down the skin.

How to Get Wet Skin in Daz Studio Iray

1. Making the composition fit

First, I create my scene in Daz Studio. Since I want to focus on the skin, I want my figure to be fairly large, and to have a good amount of skin visible. In addition, she should be doing something that will result in wet skin. In this image, I decided to create a dynamic scene, featuring Victoria 7 exercising with weights. Hair is NJA Ponytail Hair, which is one of my favorites. Outfit is Heat Up for G3F and G2F.

Below is the first pass of my composition with regular Victoria 7 skin. Lighting is just with an IBL. At this point, the skin does not look very wet.

Woman exercising with weights with regular Victoria 7 skin.

2. Making the skin properly shiny

Next, I want to change certain settings on my Victoria 7 skin to make it more shiny. To do this, I select my Victoria 7 figure, and go into Surfaces > Editor. I select my V7 skins and make the following parameter changes –

• Glossy Layered Weight set to 1.0.
• Glossy Reflectivity set to 0.9.
• Glossy Roughness set to 0.4. This can be set lower if we want to increase the wet effect on skin. Setting it too low though, will make the skin look unrealistically shiny. Therefore, tweak it according to personal taste.
• Top Coat Layering Mode set to Fresnel. Top Coat IOR set to 1.49 and Top Coat Thin Film IOR set to 1.4. Again, Top Coat Roughness can be adjusted according to taste. A lower Roughness value will increase shininess and a higher Roughness value will decrease shininess.

Victoria 7 skin after changing Glossy and Top Coat parameters.

3. Adding water drops on top of the skin

There are multiple ways to achieve this final step. I use a simple technique here, which utilizes the Daz Studio geometry shell.

• First, I select my Victoria 7 figure.
• Next, I go into Create > New Geometry Shell. This creates a shell over our Victoria 7 figure.
• I then select the Geometry Shell and apply the Iray Water shader to it.
• I go to Parameters > Mesh Offset and set the Offset Distance to 0.001.

Victoria7 after adding a geometric shell with surfaces set to the Iray water shader.

In the image above, she looks like she has cellophane wrapped all around her. This looks strange because water on our body does not form an even continuous shell. Instead, we only want certain small parts of the shell to be visible, simulating water droplets.

To do this, I do a search on “water condensation bump”. I download an appropriate black and white water condensation image, and apply that to the Cutout Opacity parameter of my geometry shell. I can then adjust the Horizontal and Vertical Tiles parameter to control how much water there is. I decided to go for the more subtle effect here with water drops that are not overly prominent.

Finally, I also add some mesh lights to further accentuate the shininess of my wet skin and shell.

Added water condensation map to our water geometric shell, so that only small parts of shell are visible. Also added mesh lights to accentuate our wet skin.

Another way to achieve water droplets on skin is to use crafted specular maps. This is what is done in Genesis 8 Wet Body Iray by SimonWM. He also has a variety of shells for the other Genesis figures. More recently, Hellboy released Real Drops Male Edition, which looks superb. Finally, V3Digitimes also has some great wet skin products, including Wet And Tanned Skins For Genesis 8 Female(s).

In the image below, I used Wet Body Geometry Shells by SimonWM. This is what I did –

• I apply the Wet Body geometry shell to a G2F figure (Victoria 6).
• I select all surfaces on the geometry shell and apply the Iray Uber shader.
• I set Glossy Weight to 1.0, Glossy Reflectivity to 1.0, and Glossy Roughness to 0.
• Finally, I can further control the strength of the drops by changing Translucency Weight. A value of 0 has the strongest wet map.

Water Goddess image with stronger Sweat Rolling specular wet body map.

This first image has a stronger wet body look, and uses the specular Sweat Rolling map. For contrast, we also use a more subtle wet body look, and the Water Beads specular map.

Water Goddess image with more subtle Water Beads specular wet body map. Also using more fantasy lighting here.

The image below is the finished product of my water shader experiment. In this tutorial, I talk about the different parameters of the Iray water shader, and what I focused on to create my pin-up render.

Water Shader Tutorial for Daz Studio Iray

1. Water Shader

Barcelona Sunset environment map with zero rotation.

I create the scene as I normally would. Here I am using FWSA Gillian HD and LF Sorbet Swimwear, which fits in very well with a water pin-up scene. The only extra change I made here, is to make her skin appear more wet by increasing Glossy Reflectivity to 0.9, and decreasing Glossy Roughness to 0.4, for all skin surfaces.

Once I am done, I make a plane primitive and apply the Iray water shader to it. When I look at the surface properties of my water plane, there are two key properties – reflection and refraction.

a) Reflection

To get a good reflection on my water, I want to pick a good environment map and rotation angle. I like the Barcelona Rooftops HDR that I got from sIBL Archives, so I use it here, starting with zero rotation. Unfortunately, at this rotation, it is filled with large buildings and palm trees, which is not a very pleasing reflection on my water. Therefore, I adjust the rotation until I get an interesting far-away skyline, that I am happy with (rotation = 270 degrees).

I adjust the rotation of my Environment Map until I get a more open, far-away, skyline that I am happy with.

b) Refraction

Slight change of the camera angle so we can see more of the refracted foot.

Another important aspect of the Iray water shader is refraction. Light travels at a different speed in air than in water. Therefore, when light enters water, it gets bent (at the point of crossing), thereby allowing us to see more of the leg that is submerged. Without refraction, her foot would not be visible.

Submerged objects always appear to be shallower than they are because the light from them changes angle at the surface, bending downward toward the water.
~~[HyperPhysics]

Create a Ground Plane by duplicating my water plane.

However, because all we have is our water plane and there is no ground plane, her foot looks like it is not standing on anything. To fix this, I duplicate my water plane by going into Edit > Duplicate > Duplicate Node(s). This creates a duplicate plane which I call ‘Ground Plane’. Next, I apply the Concrete Iray shader to my ground plane, and then move it down so that my pin-up girl is standing on it.

Notice that there is now a shadow under her foot, and there are also interesting patterns on the water due to refraction of the ground plane.

I add a ground plane so that the pin-up girl’s refracted foot, under the water, is standing on a solid surface.

c) Waves

You will notice, that there is wind in our render that is blowing out our pin-up girl’s hair. This wind will also create waves/ripples on our water. To add waves to our currently flat water plane, we add in an appropriate normal map. We can do a search for “water normal map” or we can get a normal map from one of our existing environments.

Load my water normal map into the Normal Map parameter of my water plane.

Next, I edit my water plane surface, and load in my water normal map. I can increase the number of Horizontal and Vertical Tiles in my shader parameter, if I want to make my water be more wavy. Finally, I can also color my water plane, for example make my water appear more blue, by changing the Base Color parameter of my water plane.

Added waves on my water plane by loading in an appropriate water normal map.

2. Water Thin & Water Dispersive

The Water Thin Iray shader is just like the Water shader except that it has the Thin Walled parameter turned on. This just means that the water shader is only applied to the surface of the object, instead of the entire volume of the object.

Thin Walled – This property sets the volumetric effects of the surface. Compare a bubble (on) to a marble (off) for example.
~~[Daz Documentation Center]

When Thin Walled is Off, the bubbles look like droplets of water.

For example, cornea surfaces are often set to Water Thin. Another great example of a thin surface object are bubbles. In my first bubble image, I have the Thin Walled parameter set to Off. In this example, my bubbles look more like droplets of water rather than bubbles.

When Thin Walled is On, the bubbles look a lot more like bubbles.

Completed Pink Lady and Bubbles image.

Another very cool aspect of bubbles is that they have chromatic dispersion. These result in the many colors we may see on bubbles, in an oil slick, or in a rainbow.

A bubble film is a sort of sandwich: a layer of soap molecules, a filling of water molecules, and then another layer of soap molecules. When light waves reflecting from one layer of soap molecules meet up with light waves reflecting from the second layer of soap molecules, the two sets of waves interfere. Some waves add together, making certain frequencies or colors of light brighter. Other waves cancel each other, removing a frequency or color from the mixture. The colors that you see are what’s left after the light waves interfere.
~~[Exploratorium]

That is what the Water Dispersive Iray shader addresses. It has an additional parameter called Abbe.

Abbe is a conatant chromatic dispersion. Lower numbers (but greater than 0) give more dispersion on the surface, and the higher the value, the less dispersion. This works on surfaces with volume, not on Thin Walled surfaces.
~~[Daz Documentation Center]

Note that Abbe does not work on Thin Walled surfaces. Therefore, to test this out, I need a double layered bubble (i.e. a bubble that is geometrically represented by both an outer and inner layer). I found such a bubble in the 3D Bubbles product by MindVision G.D.S.

Water Dispersive Iray shader applied to two-sided bubbles. Abbe set to 2.

Chromatic dispersion works here. However, the two sided bubbles look a bit too substantial for bubbles, and ends up looking more like glass. Personally, I like the Thin Walled version best.

Another example image with Thin-Walled bubbles.

3. Under-Water Scene

There are two important aspects in an underwater scene, volumetric or atmospheric effects and caustics. I achieve my underwater atmospheric effect by using AtmoCam for Iray by Marshian. We can also set up our own volumetric cube by following some of the guidelines discussed here (in the Daz3D forum).

In optics, a caustic or caustic network is the envelope of light rays reflected or refracted by a curved surface or object, or the projection of that envelope of rays on another surface.
~~[Wikipedia]

In water, cool caustic patterns are made by the curves of surface waves. To generate these caustic patterns in my underwater scene, it is easiest and most time effective to fake it using a Gobo light.

1. I first did a search for “water caustics texture” and download some patterns that I like.
2. Then, I placed a spotlight up high up in my scene, and point it down at my focus area. I want it high enough so that it casts a bunch of almost parallel rays into my scene.

I invert my caustics image using the Layered Image Editor.
3. Next, I create a plane and apply my water caustics texture to the Cutout Opacity parameter of the plane. White represents opaque and black represents transparent. Therefore, I want my caustics lines to be in black and all the rest to be in white. If necessary, I can invert the image using the Layered Image Editor.
4. Finally I position the plane in front of my light so that it casts the proper shadows onto my underwater floor plane.

Finished underwater mermaid scene with caustics from a Gobo light.

Another way to achieve caustics is to do it for real by setting up an appropriate scene with appropriate shaders, and then letting the Iray renderer physically generate the water caustics pattern. This will take much longer to render, but will create more realistic looking results.

It was a big challenge for me to get Iray to generate caustic patterns in my underwater scene. I was finally only able to do it by using Overcomeon’s underwater caustic test scene.

Remember that the caustic patterns are formed by reflection and refraction off the curved surface of waves, on our water. Therefore, we will need waves on our water plane. In addition, reflection also plays a very important role to bounce off our light rays, thereby increasing the area where the patterns are created. To get caustics in my scene, I needed to place several large planes around my scene to bounce off my sunlight.

Finally, we also want to go to Render Settings > Optimization and turn ON the Caustic Sampler parameter. This will hopefully increase render efficiency of caustics in our scene. Note that this is just an optimization or render efficiency setting.

Finished underwater mermaid scene with real caustics from the Daz Studio Iray renderer.

However, one of the key weaknesses of Daz Studio Iray is the difficulty of finding information on how to use it effectively, and how its’ new features can help to enhance my art. There is a lot of good stuff in the Daz3D forums, however one usually has to wade through pages and pages of images and posts, before getting to anything that helps.

Here, I want to list some of the useful Iray tips and tricks that I learned from the Daz forums, from talking to other Dazaholics, and from my own experiments with Daz Studio Iray. If you know of any additional Iray techniques, please let us know in the comments section below.

Daz Studio Iray Tips ad Tricks

1. Mesh Lights

Mesh lights are extremely useful for lighting an Iray scene because it provides soft and more realistic shadows. One of the best ways to get a mesh light in Iray, is to convert a spotlight into a mesh light. We can easily do this by –

1. Select our spotlight and click on the parameters tab.
2. Click on Light > Area.
3. Set the Light Geometry drop-down menu to Rectangle, and set the height and width parameters according to the mesh light size that you want. A larger mesh light will product softer shadows, and a smaller mesh light will produce harder shadows.

How to change a spotlight into a mesh-light.

And that is it! Our spotlight has now become a mesh light, and the really cool advantage is that we can still change our camera to the spotlight view, and see exactly what it lights. Similarly, we can change a point light into a sphere, so that it produces softer shadows.

I usually use an IBL to provide ambient light in my scene, and multiple mesh-lights to further accent my figure(s). In the scene below, I only used two mesh-lights.

Soft shadow pin-up scene of woman in heels. Only used two mesh-lights in this scene.

2. Fuller Hair

Example of thin, wispy hair in Daz Studio Iray.

A common problem that I faced in Iray is that certain hair props or figures may appear very wispy or thin. As I understand it, this is a problem with the hair transparency map not being strong enough, i.e. not white enough.

Hair is thicker and fuller now with the Cutout Opacity parameter set to 2.

One very easy way to fix this problem is to –

1. Select our hair object and click on the Surfaces tab.
2. Select all the relevant hair surfaces, and look for the Cutout Opacity parameter.
3. Remove the limits on the Cutout Opacity parameter. To do this, click on the gear icon to the right and select Parameter Settings (see below). Then, un-check the Use Limits box and click Accept in the pop-up box.
4. Set the Cutout Opacity parameter to a value greater than 1 depending on how much we want to strengthen the visibility of our hair strands. Setting a value that is too high may make things too strong, and lose the wispy look of our outer hair strands.

How to remove the max limit on our hair Cutout Opacity parameter.

Un-check the Use Limits box and click Accept

One very important thing to note is that removing the limits on the Cutout Opacity parameter, also changes the transparency map of all selected surfaces to the same image. Therefore, if we are changing several surface layers at once, we need to make sure that all their transparency maps match. Otherwise, the wrong transparency map will be used.

Instead of using Cutout Opacity, we may also lighten our transparency map in a separate image editing software. This method gives us more control over which parts of the hair we want to strengthen, and which parts we want to leave wispy.

What I do in Photoshop –

1. Load my hair transparency map.
2. Duplicate the transparency map into an additional layer.
3. Set the layer blending option of my duplicate layer to Screen.
4. I can change the opacity of this layer to control how much additional volume I want to add to my hair. I can also use masks to control which area I want to strengthen.
5. Once I am happy with the results, I merge both layers and save the transparency image to a new file.
6. I replace the transparency map, in the Cutout Opacity parameter, with this new Photoshop-ed image.

I got this tip from Fred Winkler Art. Many thanks Fred! 😀

Using UHT Hair Shaders for Iray by Slosh.

Instead of mucking with transparency maps and fiddling with hair surface parameters, we can also use UHT Hair Shaders for Iray by Slosh. So far, I am very happy with this product.

• It is easy to use,
• I like the extra displacement and shine options it provides, and
• It produces good results in most of my renders.

Lady with red hair, using UHT Hair Shaders for Iray by Slosh.

3. Shiny Eyes

Eyes appear shiny when the surface of our eye reflect the strong light sources in the environment. Therefore, to get lively, shiny eyes, there has to be one or more properly placed light sources to reflect off of.

For example, in the hair examples above, her eyes are shiny because they are reflecting some of the strong light areas in my IBL (image based light). Rotating my image map differently, will result in different eye reflections.

Sometimes, our light source may be properly placed, but the area of the eye that it affects (i.e. the area of reflection) may be too small to be discernible in my rendered image. In this case, we may increase the area of reflection by increasing the amount of cornea bulge in our figure.

Left – Cornea Bulge set to maximum, larger reflection. Right – Cornea Bulge set to minimum, smaller reflection.

To achieve this –

1. Select our figure and click on the Shaping tab.
2. Open up our figure and click on the Eyes section.
3. Enter cornea into the search box at the top to filter the shaping parameters that are shown.
4. Set the Eyes Cornea Bulge parameter to maximum.

How to change the area of eye-reflection on our figures.

Victoria 7 swimsuit pin-up with shiny eyes and cornea bulge set to maximum.

4. Metal Shader Textures

(A) Knight in armor after applying Iray Uber shaders.

One of the early problems I encountered with Iray is how to have my original armor textures show, after I apply an Iray metal shader. For example, I am creating a knight in armor image (A) using Luthbel’s Paladin armor for G2M.

First of all, I just apply the Iray Uber shader to all the objects in my scene.

Next, I want to further refine my armor surfaces. In particular, I want to apply metal surfaces to appropriate parts of my knight’s armor. I also change the cloth surfaces to Iray velvet, and the leather surfaces to Iray leather.

(B) Knight in armor after applying Iray Steel-Galvanized shader.

In the next image (B), I Ctrl-clicked on the Iray Steel-Galvanized metal shader, so that my original textures are preserved, but still, the armor appears a flat shade of silver. All my original texture colors are not showing. Why?!

This is because my armor texture only appears in the Base Color parameter. However, for some metal shaders, there is a much stronger, additional, Metallic Flakes layer.

How to have my original armor textures show after applying an Iray metal shader.

If I want my original armor textures to show, I will need to load those textures into the Metallic Flakes Color parameter.

1. I go into the surfaces tab.
2. I select all the metal surfaces on my armor object.
3. I note which image map is used in the Base Color parameter, and apply the same image to the Metallic Flakes Color parameter.

After I apply the Base Color image maps to the Metallic Flakes Color parameter, I get a more metallic looking armor with my original textures (C) – Success!!

(C) Knight in armor after setting the Metallic Flakes Color image map, to my original armor textures.

Next, I can enhance the glossiness of my metal surfaces by –

1. Setting Glossy Weight to 1,
2. Removing the image map from Glossy Color,
3. Setting the Glossy Color to an appropriate color. In this way I can tint my armor to whatever I want. For example, in this composition I want my armor to appear somewhat golden, so I play around with the Glossy Color until I find something that I am happy with. Once I find it, I drag and drop that color into my Custom colors panel so that I can easily apply it to other metal surfaces.

How to increase the glossiness of our armor and tint it appropriately.

Now that I have all the materials set up properly, I add in some lights to highlight my figure, and then finish with some post-work in Photoshop.

I am still learning the ins and outs of Iray, so if you have more Iray tips, please post them in the comments section below. Many thanks!

Final Golden Knight image with post-work in Photoshop.